Hi there I have a stud dog who had successfully mated and had litters 4 times. He has never had problems with any previous mates. We have had a bitch come 3 times now on days 14, 12 and 11. They haven’t successfully tied on any. Which days I’m seasom are best for maiden bitches? Or is it so dependent on the individuals? 3 our of 4 Of the previous mates were maiden never had this issue before. He’s definitely penetrating but isn’t staying in for long. Does anyone have advice?